Write protection: You can adjust a diskette so the information on it can't accidentally be erased or changed. On one of the corners there's a small tab in a groove that you can
slide (see the above illustration). When you slide it so you can see a hole all the way through the diskette, it's now "write protected" and can't be changed or erased.

Care of diskettes:
Don't put near strong magnets
Protect from extreme heat or cold (don't leave them in your car on a hot day)
Don't bend or touch the magnetic disk that's inside.

A hard drive looks like a small record; it isn't removable the way a floppy is. Hard drives, like diskettes, store information magnetically.

Hard drives are much faster than floppies, but since they aren't removable they have to be "backed up" to something that is removable. Most hard drives are installed inside the computer box but "external" hard drives are also available that plug into the back of the computer.

Give the size of today's programs and graphic files, you should get a hard drive
with a capacity of at least 10 gig, preferably more.

These are "optical" disks, not magnetic disks. It's a slow process to record information on them but the retrieval time is very good. Their greatest advantage is that they can store about 630meg (630,000,000 characters), or about the same amount as 450 floppy disks, and they're removable as well.

There are two basic types of CD drives for PC's:

CD-ROM

(Compact Disk, Read Only
Memory)
This type of CD drive can only read, or retrieve, information. New software that you purchase typically comes on a
CD-ROM.

CD-RW

(Compact Disk,
Re-writeable).
This type of CD drive can write and re-write information on CD's. If you're going to get a CD drive for your computer, pay a little more and get the
CD-RW (rewriteable) version.

There are two types of CD's (the disks themselves) that are used by
a CD-RW:

CD-R

you can record information on them only once; typically used to share information with another
computer

CD-RW

have the ability to record information in many different sessions. The
CD-RW CDs are much more expensive initially, but since they can be re-used many times their cost over time is less.

This type of optical disk can hold up to 4.7 gig (4,700,000,000 bytes). This is the equivalent of 28 CD's (or over 12,000 diskettes!).
They are up to 8 times as fast, and can be played on TV's as well.
They
are expected to eventually replace CD-ROM's in the market.

If your business relies on a
database and you're doing a Grandfather - Father - Son backup procedure,
which requires 12 different backups, this is the cheapest way to go.
The tape player is available for a few hundred dollars and each tape is
$50 or less.

However, tapes are very slow. Recording speed is much slower than a
removable hard drive. Even worse, if you're trying to restore just a
single file, it can take a maddeningly long time for the tape to wind
forward or backwards to the correct location.